Yeah, so. I have this optical mouse, which a I love, seeing as how I can use it on pretty much any surface.
Sometimes when I’m feeling too lazy to actually sit up straight, I recline in my chair while surfing the internet or reading these boards and use my knee or arm of my chair with the mouse.
But something about being exposed to oddly sensitive red lights is vaugly disconcerting.
So am I in any danger? Is my leg going to fall off? Assuage me!
No. Red light has a much longer wavelength than UV. It is incapable of causing any damage.
I’m sure that optical mice will give you cancer eventually, if you eat enough of them.
No the mouse is fine. You need to worry more about sitting on your rear end for hours at a time eating sandwiches, chicken pot pies and ice cream while your arteries clog and your ass gets fatter. If it keeps up… well you might have to buy a new wider chair to accomodate your gigantic bulk while you post.
The light source on an optical mouse is a red LED. I can’t imagine a light source safer than that.
I use an optical mouse. I just had six skin cancers removed. Beware.
My friend had a skin cancer removed last summer and he’s in law school. Law School gives you cancer!
scr4 is right. If your mouse is gonna give you cancer, watch out for your HD light, VCR and clock-radio. 
I don’t have skin cancer, but a my gf had a benign melanoma removed over a year ago.
I give you cancer!
And in Soviet Russia, cancer gives you to me! Bwah-hah-hah-hah-hah…
I have an optical mouse that has a blue LED (for effect only) in the top shell - this is right under my palm when I use it.
Now I think I’m right in saying that blue LEDs do emit some ultraviolet; am I at risk?
Very very little. And what there is of it is longwave near-UV which isn’t nearly as damaging as the shortwave UV you’re exposed to from sunlight.
Only if it takes up smoking cigarettes while you’re in the room.